Some of the disclosed embodiments monitor patient orientation and/or movement, such as patient incline angles and changes of those angles for various purposes. Some of these and/or other embodiments monitor various types of patient movement, including movements caused by respiration and/or heartbeats.
The related art includes various apparatus for monitoring patient incline angles. A few such examples are disclosed below.
I. US 2005/0237209 to Van Dongen
Van Dongen provides a very short disclosure that is directed to improving posture awareness for the purpose of preventing back pain. A device 10 is strapped around a patient's sternum. The device includes an inclinometer 26, which is disclosed as a being an accelerometer (paragraphs [0015] and [0033]), and in particular like the one “marketed under the reference ADXL202EB by the firm Analog Device.”
The inclinometer 26 supplies a signal representing the angle of inclination of the sternum relative to a vertical line to a calculator 28. The calculator 28 measures the angle of inclination, compares the measurement with two stored threshold values of the angle, which correspond to forward leaning and backward leaning positions that constitute a pathological risk for the patient, and produces an indication of the threshold values being exceeded. An indicating means can include a light, acoustic, and/or vibrating alarm. The device can also include memory that enables the calculator 28 to count the number of breaches of the forward and backward threshold values observed during a certain time slot.
II. US 2008/0294022 to Sharf et al.
Sharf provides a moderately detailed disclosure that is directed to a medical monitor for measuring patient physiological parameters relating to the progress of birthing, and providing an output based on the measurements. The output is modified based on a patient's posture, i.e., lying on back, lying on side, walking, etc., in order to take into account maternal geometry changes caused by changes in the mother's position.
The posture is determined using an inclination sensor 130 (380), which can be a tilt meter (such as an acceleration meter, beam with strain gauge, or gravity direction detector) or known inclinometer such as is disclosed in Chapter 15 of “The measurement, Instrumentation and Sensors Handbook (ISBN: 0-8493-8347-1),” dated 1999. See paragraphs [0007] and [0087]. Multiple sensors 130 can be used and positioned on any part of the patient's body, including the abdomen, trunk, spine, arm, leg, etc. The sensor 130 can notify a monitor 120 (such as by initiating an alarm, displaying measurements, etc.) when a change in position occurs, such as a change in inclination by more than 30 or 45 degrees relative to the normal. Alternatively, the sensor 130 can notify the monitor 120 of patient inclination periodically, continuously, when a significant change occurs, at set intervals, etc.
III. US 2010/0145235 to Goldbeck et al.
Goldbeck provides a very short disclosure that is directed to a device for fixing at least one fibrous strip FB to a patient's body part for the purpose of measuring bending angles (flexions and torsions), such as the bending angle of the patient's spine. The fibrous strip includes at least one fibre-optic sensor with multiple sensitive zones. Bending angles are determined based on variance of light attenuation as a function of the bending angle of the fiber optic sensor.
A fixing unit includes a fixing part BM for applying part of the fibrous strip to the body part, and a fixing loop BS for guiding the fibrous strip along an axis of three-dimensional space. This sensor provides reliable measurements because the fibre sensor follows the curvature of the body and the fixing unit avoids slippage even during patient movement.
IV. U.S. Pat. No. 8,401,666 to Skelton et al.
Skelton provides a very detailed disclosure that is directed to adjusting parameter values for stimulation therapy based on detected patient activity, such as a change in the patient's posture. In other words, certain therapy modifications are applied for different changes in the patient's detected posture. An implantable medical device (IMD) 14, such as an implantable neuro-stimulator, is implanted within a patient's body to provide neuro-stimulation therapy. The IMD 14 may operate with implantable leads, or alternatively be a leadless stimulator that operates with one or more arrays of electrodes arranged on an external housing.
A posture state module 86 allows the IMD 14 to sense the patient's posture state, e.g., posture, activity or any other static position or motion of the patient 12. The posture state module 86 includes one or more accelerometers, such as three-axis accelerometers and/or micro-electro-mechanical accelerometers, capable of detecting static orientation or vectors in three dimensions. Alternatively, the posture state module 86 can include one or more gyroscopes, piezoelectric crystals, pressure transducers or other sensors to sense the patient's posture state. The generated posture state information may correspond to an activity and/or posture undertaken by the patient 12 or a gross level of physical activity. The posture state module 86 may also be configured to sense one or more physiological parameters, i.e., heart rate, temperature, respiratory rate, pH, etc. (See Col. 18, posture state module 86 lines 50-64; and col. 19, line 64-col. 20, line 7. In response to the posture state information received from the posture state module 86, the IMD 14 may change program groups, stimulation amplitudes, pulse widths, pulse rates, etc. (See col. 10, lines 24-39).
V. U.S. Pat. No. 8,002,465 to Ahn
Ahn provides a very detailed disclosure that is directed to real time targeted delivery of radiation or nuclear medicines for diagnostic or therapeutic purposes by accurately measuring patient position. A plurality of sensors are arranged, such as in an array, on a table or flat surface, or in a mask or mold of the abdomen and/or pelvis, to assess the patient's position. The sensors can be removably attached with an adhesive or permanently attached to an immobilization device. The sensors are directed to ensuring that the patient is positioned during treatment in an orientation that is identical to the original planning scan.
VI. U.S. Pat. No. 7,833,188 to Gerber
Gerber provides a very short disclosure that is directed to a patient angle sensor that is used with gastric feeding devices to shut off or reverse the flow of fluid in a tube when the angle of a bed ridden patient becomes sufficient to allow gastric juices to percolate up through the esophagus and into the lungs, which can result in aspiration pneumonia. A sensor senses when a patient slides down below a certain predetermined angle, and turns off a pump to prevent further fluid from entering the stomach and hence the esophagus. When the device senses that the patient's orientation is below a certain angle, the hospital staff can be alerted, and the head or foot portion of the bed may be raised to prevent further downward sliding.
A sensor 200 is placed at the patient's chest, and can be affixed to the patient directly (such as by adhesives) or to the patient's clothing. The sensor 200 can be any device that senses angles, and can include a wide range of sensing technologies, such as mercury filled insulative containers with electrical contacts, magnetic sensors, optical sensors, etc. More sophisticated sensors can be used that provide a signal indicative of the actual angle of orientation of the patient, as opposed to the angle merely exceeding a threshold value, which may provide early warning of a patient sliding downward.
VII. U.S. Pat. No. 7,002,482 to Callaway
Callaway provides a very short disclosure that is directed to remote monitoring of bedridden patients to prevent injurious falls should the patient attempt to get out of bed. A mercury switch is only actuated when the patient moves a certain way. An internal cavity of the switch controls movement of a mercury ball 15 into and out of engagement with two electrical contacts. The internal cavity has a truncated cone for receipt of the mercury ball, a surface of revolution sloping outward from the opening of the truncated cone, and an interruption ramp 19 in the surface of revolution to guide the mercury ball into the truncated cone for actuation of a switch when a critical angle of the switch has been exceeded. (See col. 1, lines 43-54; and col. 3, lines 46-55).
VIII. U.S. Pat. No. 4,348,562 to Florin
Florin provides a very short disclosure that is directed to a mercury switch assembly that is secured to an anterior horizontal surface of a patient for the purpose of detecting certain angular deviations of the patient's body. The switch is connected to an electrical alarm system to warn an attendant of certain patient movements that may precede a fall, i.e., change from a horizontal position of an anterior surface of the chest or thigh to a more vertical position.